Methods and systems for facilitating stimulation of one or more stimulation sites

ABSTRACT

Methods of facilitating stimulation of a stimulation site within a patient include implanting a distal portion of a first stimulating member such that the distal portion of the first stimulating member is in communication with a first stimulation site located within a patient, securing the distal portion of the first stimulating member at a first securing site with a first securing device positioned proximal to the first stimulation site, forming a first loop of at least 360 degrees with a portion of the first stimulating member proximal to the first securing device, securing the first loop with a second securing device at a second securing site having a position that is greater than or equal to substantially 180 degrees but less than or equal to substantially 315 degrees along the first loop from the first securing site, and positioning the second securing device and a stimulator to be coupled to a proximal end of the first stimulating member to maintain a curve in the first stimulating member of at least 45 degrees between the second securing device and the stimulator.

RELATED APPLICATIONS

The present application is a divisional application of U.S. application Ser. No. 11/728,816 filed Mar. 26, 2007, which application is a continuation-in-part application of U.S. application Ser. No. 11/259,176, filed Oct. 25, 2005, which application claims the benefit of U.S. Provisional Application Ser. No. 60/661,700 filed Mar. 14, 2005. All applications are incorporated herein by reference in their respective entireties.

BACKGROUND

The public health significance of many medical, psychiatric, and neurological conditions and/or disorders is often overlooked, probably because of their episodic nature and the lack of mortality attributed to them. However, some medical conditions, such as headaches and facial pain, are often incapacitating, with considerable impact on social activities and work, and may lead to the significant consumption of drugs.

Migraine headaches are a particular form of headache, usually very intense and disabling. Migraines are a neurological disease thought to be of vascular origin. They are characterized by attacks of sharp pain usually involving one half of the skull and may be accompanied by nausea, vomiting, phonophobia, photophobia and occasionally visual, olfactory or balance disturbances known as aura. The symptoms and their timing vary considerably among migraine sufferers and, to a lesser extent, from one migraine attack to the next. Migraine is often connected with the expansion of the blood vessels of the head and neck.

Conventional treatments for migraines focus on three areas: trigger avoidance, symptomatic control, and preventive drugs. Each of these will be discussed below.

In a minority of patients, the incidence of migraines can be reduced through diet changes to avoid certain chemicals that serve as triggers for migraines. These chemical triggers may be present in such foods as cheddar cheese and chocolate, and in most alcoholic beverages. Other triggers may be situational and some can be avoided through lifestyle changes. Such triggers may include particular points in the menstrual cycle, certain weather patterns, or hunger. Bright flashing lights may also be a trigger. Most migraine sufferers are sensitive to and avoid bright or flickering lights.

If a migraine occurs despite trigger avoidance, the next step in treatment is symptomatic control. Caffeine and simple pain killers, analgesics, such as paracetamol, aspirin or low doses of codeine are sometimes, but not often, effective. Narcotic pain medications, such as heroin, morphine, and other opiates, provide variable relief. However, many of these drugs are addictive and can cause undesirable side effects.

Various drugs may also be administered on a regular basis to prevent the onset of migraines. Exemplary preventive drugs include beta blockers (e.g., propranolol or atenolol), antidepressants, and antispasmodic drugs. However, many of these drugs are ineffective in preventing migraines.

SUMMARY

Methods of facilitating stimulation of a stimulation site within a patient include implanting a distal portion of a first stimulating member such that the distal portion of the first stimulating member is in communication with a first stimulation site located within a patient, securing the distal portion of the first stimulating member at a first securing site with a first securing device positioned proximal to the first stimulation site, forming a first loop of at least 360 degrees with a portion of the first stimulating member proximal to the first securing device, securing the first loop with a second securing device at a second securing site having a position that is greater than or equal to substantially 180 degrees but less than or equal to substantially 315 degrees along the first loop from the first securing site, coupling a proximal end of the first stimulating member to a stimulator, and positioning the stimulator and the second securing device to maintain a curve in the first stimulating member of at least 45 degrees between the second securing device and the stimulator.

Systems for facilitating stimulation of a stimulation site within a patient include a first stimulating member having a distal portion configured to be in communication with a first stimulation site within a patient and a proximal portion configured to be formed into a first loop of at least 360 degrees, a stimulator coupled to a proximal end of the first stimulating member, and first and second securing devices configured to secure the first stimulating member to at least one securing site. The first securing device is configured to secure the distal portion of the first stimulating member at a first securing site and the second securing device is configured to secure the first loop at a second securing site having a position that is greater than or equal to substantially 180 degrees but less than or equal to substantially 315 degrees along the first loop from the first securing site. The second securing device is further configured to maintain a curve in the first stimulating member of at least 45 degrees between the second securing device and the stimulator.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various embodiments of the principles described herein and are a part of the specification. The illustrated embodiments are merely examples and do not limit the scope of the disclosure.

FIG. 1A depicts the upper cervical spine area of a patient and shows a number of nerves originating in the upper cervical spine area.

FIG. 1B depicts the occipital nerves in the back of the head and upper neck area of a patient.

FIG. 1C illustrates a view of the major nerves and arteries in the human head as viewed from above looking down on the top or superior part of the head.

FIG. 2 illustrates an exemplary implantable stimulator according to principles described herein.

FIG. 3 illustrates an exemplary microstimulator according to principles described herein.

FIG. 4 shows an example of a microstimulator with one or more leads coupled thereto according to principles described herein.

FIG. 5 depicts a number of stimulators configured to communicate with each other and/or with one or more external devices according to principles described herein.

FIG. 6 illustrates an exemplary lead configuration according to principles described herein.

FIG. 7A is a perspective view of an exemplary suture sleeve according to principles described herein.

FIG. 7B is a top view of the suture sleeve illustrated in FIG. 7A according to principles described herein.

FIGS. 7C-7D show perspective views of additional exemplary suture sleeves according to principles described herein.

FIG. 8 illustrates another exemplary lead configuration according to principles described herein.

FIG. 9 is a cross-sectional view of an implanted suture sleeve according to principles described herein.

FIG. 10 is a flow chart illustrating an exemplary method of facilitating stimulation of one or more stimulation sites within a patient according to principles described herein.

Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.

DETAILED DESCRIPTION

Methods and systems for facilitating stimulation of at least one stimulation site within a patient are described herein. The methods and systems may be used to treat a variety of medical conditions such as, but not limited to, headaches, occipital neuralgia, facial pain, and/or conditions treated with spinal cord stimulation.

In some examples, a distal portion of a stimulating member (e.g., a lead and/or a catheter) is implanted such that it is in communication with a stimulation site located within a patient. A first securing device may then be used to secure the distal portion of the stimulating member at a first securing site positioned proximal to the stimulation site. A loop of at least 360 degrees may then be formed with a portion of the stimulating member that is proximal to the first securing device. The loop may be secured with a second securing device at a second securing site having a position that is greater than or equal to substantially 180 degrees along the loop from the first securing site but less than or equal to substantially 315 degrees along the loop from the first securing site. The stimulator (which will be coupled to the proximal end of the stimulating member) and the stimulating member may be positioned to maintain the loop and to maintain a curve in the stimulating member of at least 45 degrees between the second securing device and the stimulator.

In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present systems and methods. It will be apparent, however, to one skilled in the art that the present systems and methods may be practiced without these specific details. Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearance of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.

FIG. 1A depicts the upper cervical spine (C1-C4) area of a patient. As shown in FIG. 1A, a number of nerves arise from the upper cervical spine (C1-C4). Examples of such nerves include, but are not limited to, the greater occipital nerve(s) 101, lesser occipital nerve(s) 102, greater auricular nerve(s) 103, transverse cervical nerve(s) 104, supraclavicular nerve(s) 105, and/or branches of any of these nerves.

FIG. 1B depicts the occipital nerves 100 in the back of the head and upper neck area of a patient. As shown in FIG. 1B, the occipital nerves 100 are divided into greater 101 and lesser 102 occipital nerves. The occipital nerves 100 lie subcutaneously in the back of the head and upper neck and are therefore are relatively easily accessed.

FIG. 1C illustrates a view of the major nerves and arteries in the human head as viewed from above looking down on the top or superior part of the head. As shown in FIG. 1C, the greater occipital nerves 101 extend to and across some of the top or superior portion of the head. The lesser occipital nerves 102 may also extend to or near the top or superior portion of the head.

It is believed that applying a stimulus to one or more of the nerves within in the head and/or neck may be effective in treating one or more medical conditions. For example, the stimulus may be configured to alleviate or eliminate headache. However, it will be recognized that any other medical condition (e.g.; occipital neuralgia, facial pain, conditions treated with spinal cord stimulation, etc.) may be treated in accordance with the systems and methods described herein.

Consequently, a stimulator may be implanted within a patient to deliver a stimulus to one or more stimulation sites within the head and/or neck in order to treat one or more medical conditions. The present specification describes methods and systems for implanting such a stimulator within the patient.

The stimulation sites referred to herein may include any nerve, tissue, blood vessel, or other area within a patient. It will be recognized that although the exemplary stimulation sites described in connection with the examples given herein are located within the head and/or neck, one or more of the stimulation sites may additionally or alternatively be located anywhere within a patient. For example, the methods and systems described herein may be used in connection with spinal cord stimulation, wherein the stimulation site is located along the spinal cord and wherein the stimulator is implanted at a surgically convenient location (e.g., within the buttocks).

As used herein, and in the appended claims, the term “stimulator” is used broadly to refer to any device that delivers a stimulus, such as an electrical stimulation current, one or more drugs, chemical stimulation, thermal stimulation, electromagnetic stimulation, mechanical stimulation, and/or any other suitable stimulation to a stimulation site. Thus, the term “stimulator” includes, but is not limited to, a microstimulator, an implantable pulse generator (IPG), a system control unit (stimulator), an external trial stimulator, or similar device.

To facilitate an understanding of the methods and systems described herein, a more detailed description of a stimulator and its operation will now be given with reference to the figures. FIG. 2 illustrates an exemplary stimulator 120 that may be used to apply a stimulus to a stimulation site within a patient, e.g., an electrical stimulation of the stimulation site, an infusion of one or more drugs at the stimulation site, or both. The electrical stimulation function of the stimulator 120 will be described first, followed by an explanation of the possible drug delivery function of the stimulator 120. It will be understood, however, that the stimulator 120 may be configured to provide only electrical stimulation, only drug stimulation, both types of stimulation, or any other type of stimulation as best suits a particular patient.

The exemplary stimulator 120 shown in FIG. 2 is configured to provide electrical stimulation to one or more stimulation sites within a patient and may include at least one lead 121 coupled thereto. In some examples, the at least one lead 121 includes a number of electrodes 122 through which electrical stimulation current may be applied to a stimulation site. It will be recognized that the at least one lead 121 may include any number of electrodes 122 arranged in any configuration as best serves a particular application.

As illustrated in FIG. 2, the stimulator 120 includes a number of components. It will be recognized that the stimulator 120 may include additional and/or alternative components as best serves a particular application. A power source 125 is configured to output voltage used to supply the various components within the stimulator 120 with power and/or to generate the power used for electrical stimulation. The power source 125 may include a primary battery, a rechargeable battery (e.g., a lithium-ion battery), a super capacitor, a nuclear battery, a mechanical resonator, an infrared collector (receiving, e.g., inffared energy through the skin), a thermally-powered energy source (where, e.g., memory-shaped alloys exposed to a minimal temperature difference generate power), a flexural powered energy source (where a flexible section subject to flexural forces is part of the stimulator), a bioenergy power source (where a chemical reaction provides an energy source), a fuel cell, a bioelectrical cell (where two or more electrodes use tissue-generated potentials and currents to capture energy and convert it to useable power), an osmotic pressure pump (where mechanical energy is generated due to fluid ingress), or the like.

In some examples, the power source 125 may be recharged using an external charging system. One type of rechargeable power supply that may be used is described in U.S. Pat. No. 6,596,439, which is incorporated herein by reference in its entirety. Other battery construction techniques that may be used to make the power source 125 include those shown, e.g., in U.S. Pat. Nos. 6,280,873; 6,458,171; 6,605,383; and 6,607,843, all of which are incorporated herein by reference in their respective entireties.

The stimulator 120 may also include a coil 128 configured to receive and/or emit a magnetic field (also referred to as a radio frequency (RF) field) that is used to communicate with, or receive power from, one or more external devices. Such communication and/or power transfer may include, but is not limited to, transcutaneously receiving data from the external device, transmitting data to the external device, and/or receiving power used to recharge the power source 125.

For example, an external battery charging system (EBCS) 111 may be provided to generate power that is used to recharge the power source 125 via any suitable communication link. Additional external devices including, but not limited to, a hand held programmer (HHP) 115, a clinician programming system (CPS) 117, and/or a manufacturing and diagnostic system (MDS) 113 may also be provided and configured to activate, deactivate, program, and/or test the stimulator 120 via one or more communication links. It will be recognized that the communication links shown in FIG. 2 may each include any type of link used to transmit data or energy, such as, but not limited to, an RF link, an infrared (IR) link, an optical link, a thermal link, or any other energy-coupling link.

Additionally, if multiple external devices are used in the treatment of a patient, there may be communication among those external devices, as well as with the implanted stimulator 120. It will be recognized that any suitable communication link may be used among the various devices illustrated.

The external devices shown in FIG. 2 are merely illustrative of the many different external devices that may be used in connection with the stimulator 120. Furthermore, it will be recognized that the functions performed by any two or more of the external devices shown in FIG. 2 may be performed by a single external device.

The stimulator 120 may also include electrical circuitry 124 configured to generate the electrical stimulation current that is delivered to a stimulation site via one or more of the electrodes 122. For example, the electrical circuitry 124 may include one or more processors, capacitors, integrated circuits, resistors, coils, and/or any other component configured to generate electrical stimulation current.

Additionally, the exemplary stimulator 120 shown in FIG. 2 may be configured to provide drug stimulation to a patient by applying one or more drugs at a stimulation site within the patient. To this end, a pump 127 may also be included within the stimulator 120. The pump 127 is configured to store and dispense one or more drugs, for example, through a catheter 123. The catheter 123 is coupled at a proximal end to the stimulator 120 and may have an infusion outlet 129 for infusing dosages of the one or more drugs at the stimulation site. In some embodiments, the stimulator 120 may include multiple catheters 123 and/or pumps 127 for storing and infusing dosages of the one or more drugs at the stimulation site.

The pump 127 described herein may include any of a variety of different drug delivery systems. For example, exemplary pumps 127 suitable for use as described herein include, but are not limited to, those disclosed in U.S. Pat. Nos. 3,760,984; 3,845,770; 3,916,899; 3,923,426; 3,987,790; 3,995,631; 3,916,899; 4,016,880; 4,036,228; 4,111,202; 4,111,203; 4,203,440; 4,203,442; 4,210,139; 4,327,725; 4,360,019; 4,487,603; 4,627,850; 4,692,147; 4,725,852; 4,865,845; 5,057,318; 5,059,423; 5,112,614; 5,137,727; 5,234,692; 5,234,693; 5,728,396; and 6,368,315. All of these listed patents are incorporated herein by reference in their respective entireties.

The stimulator 120 may also include a programmable memory unit 126 configured to store one or more stimulation parameters. The stimulation parameters may include, but are not limited to, electrical stimulation parameters, drug stimulation parameters, and other types of stimulation parameters. The programmable memory unit 126 allows a patient, clinician, or other user of the stimulator 120 to adjust the stimulation parameters such that the stimulation applied by the stimulator 120 is safe and efficacious for treatment of a particular patient. The programmable memory unit 126 may include any type of memory unit such as, but not limited to, random access memory (RAM), static RAM (SRAM), a hard drive, or the like.

The electrical stimulation parameters may control various parameters of the stimulation current applied to a stimulation site including, but not limited to, the frequency, pulse width, amplitude, waveform (e.g., square or sinusoidal), electrode configuration (i.e., anode-cathode assignment), burst pattern (e.g., burst on time and burst off time), duty cycle or burst repeat interval, ramp on time, and ramp off time of the stimulation current that is applied to the stimulation site. For example, at least one of the pulse width, frequency, amplitude, and inter-pulse interval (i.e., the delay between adjacent stimulation pulses) may be continuously adjusted to minimize patient accommodation to the stimulation.

The drug stimulation parameters may control various parameters including, but not limited to, the amount of drugs infused at the stimulation site, the rate of drug infusion, and the frequency of drug infusion. For example, the drug stimulation parameters may cause the drug infusion rate to be intermittent, constant, or bolus. Other stimulation parameters that characterize other classes of stimuli are possible. For example, when tissue is stimulated using electromagnetic radiation, the stimulation parameters may characterize the intensity, wavelength, and timing of the electromagnetic radiation stimuli. When tissue is stimulated using mechanical stimuli, the stimulation parameters may characterize the pressure, displacement, frequency, and timing of the mechanical stimuli.

The stimulator 120 of FIG. 2 is illustrative of many types of stimulators that may be used in accordance with the systems and methods described herein. For example, the stimulator 120 may include an implantable pulse generator (IPG), a spinal cord stimulator (SCS), a deep brain stimulator, a drug pump, an external trial stimulator, or any other type of stimulation device configured to deliver a stimulus to a stimulation site within a patient. Exemplary IPGs suitable for use as described herein include, but are not limited to, those disclosed in U.S. Pat. Nos. 6,381,496, 6,553,263; and 6,760,626. Exemplary spinal cord stimulators suitable for use as described herein include, but are not limited to, those disclosed in U.S. Pat. Nos. 5,501,703; 6,487,446; and 6,516,227. Exemplary deep brain stimulators suitable for use as described herein include, but are not limited to, those disclosed in U.S. Pat. Nos. 5,938,688; 6,016,449; and 6,539,263.

All of these listed patents are incorporated herein by reference in their respective entireties.

The stimulator 120 of FIG. 2 may alternatively include a microstimulator, such as a BION® microstimulator (Advanced Bionics® Corporation, Valencia, Calif.). Various details associated with the manufacture, operation, and use of implantable microstimulators are disclosed in U.S. Pat. Nos. 5,193,539; 5,193,540; 5,312,439; 6,185,452; 6,164,284; 6,208,894; and 6,051,017. All of these listed patents are incorporated herein by reference in their respective entireties.

FIG. 3 illustrates an exemplary microstimulator 130 that may be used as the stimulator 120 described herein. Other configurations of the microstimulator 130 are possible, as shown in the above-referenced patents and as described further below.

As shown in FIG. 3, the microstimulator 130 may include the power source 125, the programmable memory 126, the electrical circuitry 124, and the pump 127 described in connection with FIG. 2. These components are housed within a capsule 132. The capsule 132 may be a thin, elongated cylinder or any other shape as best serves a particular application. The shape of the capsule 132 may be determined by the structure of the desired stimulation site and the method of implantation. In some examples, the microstimulator 130 may include two or more leadless electrodes 133 disposed on the outer surface of the microstimulator 130.

The external surfaces of the microstimulator 130 may advantageously be composed of biocompatible materials. For example, the capsule 132 may be made of glass, ceramic, metal, or any other material that provides a hermetic package that will exclude water vapor but permit passage of electromagnetic fields used to transmit data and/or power. The electrodes 133 may be made of a noble or refractory metal or compound, such as platinum, iridium, tantalum, titanium, titanium nitride, niobium or alloys of any of these, in order to avoid corrosion or electrolysis which could damage the surrounding tissues and the device.

The microstimulator 130 may also include one or more infusion outlets 131 configured to dispense one or more drugs directly at a stimulation site. Alternatively, one or more catheters may be coupled to the infusion outlets 131 to deliver the drug therapy to a treatment site some distance from the body of the microstimulator 130.

FIG. 4 shows an example of a microstimulator 130 with one or more leads 140 coupled thereto. As shown in FIG. 4, each of the leads 140 may include one or more electrodes 141 disposed thereon. As shown in FIG. 4, the microstimulator 130 may additionally or alternatively include one or more leadless electrodes 133 disposed on the outer surface thereof.

In some examples, the stimulator 120 of FIG. 2 may be configured to operate independently. Alternatively, as shown in FIG. 5, the stimulator 120 may be configured to operate in a coordinated manner with one or more additional stimulators, other implanted devices, or other devices external to the patient's body. FIG. 5 illustrates an exemplary configuration wherein a first stimulator 120-1 implanted within the patient 151 provides a stimulus to a first location, a second stimulator 120-2 provides a stimulus to a second location, and a third stimulator 120-3 provides a stimulus to a third location. In some examples, one or more external devices 150 may be configured to control the operation of each of the implanted devices 120. In some embodiments, an implanted device, e.g., stimulator 120-1, may control, or operate under the control of, another implanted device(s), e.g., stimulator 120-2 and/or stimulator 120-3. Control lines 152 have been drawn in FIG. 5 to illustrate that the external device 150 may communicate or provide power to any of the implanted devices 120 and that each of the various implanted devices 120 may communicate with and, in some instances, control any of the other implanted devices.

As a further example of multiple stimulators 120 operating in a coordinated manner, the first and second stimulators 120-1 and 120-2 of FIG. 5 may be configured to sense various indicators of the symptoms or causes of a particular medical condition and transmit the measured information to the third stimulator 120-3. The third stimulator 120-3 may then use the measured information to adjust its stimulation parameters and apply stimulation to a stimulation site accordingly. The various implanted stimulators may, in any combination, sense indicators of a particular medical condition, communicate or receive data regarding such indicators, and adjust stimulation parameters accordingly.

In order to determine the strength and/or duration of electrical stimulation and/or amount and/or type(s) of stimulating drug(s) required to most effectively treat a particular medical condition, various indicators of the medical condition and/or a patient's response to treatment may be sensed or measured. The stimulator 120 may then adjust the stimulation parameters (e.g., in a closed loop manner) in response to one or more of the sensed indicators. Exemplary indicators include, but are not limited to, electrical activity of the brain (e.g., via electroencephalography (EEG)), neurotransmitter levels, hormone levels, metabolic activity in the brain, blood flow rate, medication levels within the patient, patient input, temperature of the stimulation site, physical activity level, brain hyperexcitability, indicators of collateral tissue stimulation, and/or muscle tone in neck (e.g., mechanical strain, pressure sensor, electromyography (EMG)). In some examples, the stimulator 120 may be configured to perform the measurements. Alternatively, other sensing devices may be configured to perform the measurements and transmit the measured values to the stimulator 120. Exemplary sensing devices include, but are not limited to, chemical sensors, electrodes, optical sensors, mechanical (e.g., motion, pressure) sensors, and temperature sensors.

Thus, one or more external devices may be provided to interact with the stimulator 120, and may be used to accomplish at least one or more of the following functions:

Function 1: If necessary, transmit electrical power to the stimulator 120 in order to power the stimulator 120 and/or recharge the power source 125.

Function 2: Transmit data to the stimulator 120 in order to change the stimulation parameters used by the stimulator 120.

Function 3: Receive data indicating the state of the stimulator 120 (e.g., battery level, drug level, stimulation parameters, etc.).

Additional functions may include adjusting the stimulation parameters based on information sensed by the stimulator 120 or by other sensing devices.

As mentioned, one or more stimulation sites within a patient may be stimulated by a stimulator 120 to treat a variety of different medical conditions. For example, it is believed that stimulation of one or more of the occipital nerves may be effective in treating headache. Additional or alternative stimulation sites within the head and/or neck that may be stimulated in order to treat headache include, but are not limited to, one or more of the cranial nerves, the trigeminal nerve, the infraorbital nerve, the facial nerve, the maxillary nerve, the mandibular nerve, and branches thereof.

Hence, as will be described in more detail below, one or more leads 121 with one or more electrodes 122 disposed thereon may be implanted within a patient such that the electrodes 122 are in communication with one or more stimulation sites within the patient. As used herein, the term “in communication with” refers to the electrodes 122 being adjacent to, in the general vicinity of, in close proximity to, directly next to, or directly on the stimulation site. For example, with reference to FIGS. 1B and 1C, the one or more leads 121 may be implanted in the patient's neck at or near the base of the skull, at the back of the head, on the top or superior portion of the skull, or at any other suitable location.

However, one of the issues with using a stimulator 120 with one or more leads 121 coupled thereto to stimulate a stimulation site within a patient is lead migration. For example, an implantable stimulator 120 and its associated lead(s) 121 are generally implanted on a long-term or permanent basis. However, with time and with the natural movement of the patient, a lead 121 coupled to an implanted stimulator 120 may move away from the location where it was first implanted. For example, a simple nod of the head may cause a lead 121 that is not securely implanted within the neck to shift positions. Likewise, twisting of the torso may cause a lead 121 that is not securely implanted within the back to shift positions. This tendency to move is known as lead migration, or simply, migration.

Hence, the systems and methods described herein may be used to minimize and/or eliminate lead migration. FIG. 6 illustrates an exemplary lead configuration wherein multiple leads 121 with a number of electrodes 122 disposed on a distal portion 163 thereof are implanted such that one or more of the electrodes 122 are in communication with one or more of the occipital nerves 100. The number of electrodes 122 disposed on each lead 121 may vary as may serve a particular application and lead size.

In some examples, as will be described in more detail below, each electrode 122 may be selectively programmed to have a positive (anode), negative (cathode), or OFF polarity to create a particular stimulation field when current is applied. Thus, different combinations of programmed anode and cathode electrodes 122 may be used to deliver a variety of current waveforms at one or more stimulation sites. Moreover, any of the other stimulation parameters (e.g., frequency, pulse width, amplitude, burst pattern, duty cycle, ramp on time, and ramp off time) of the stimulation current delivered by each of the electrodes 122 may be individually programmed. In this manner, as will be described in more detail below, current steering (also referred to as neuronavigation or e-trolling) may be used after the leads 121 are implanted to tailor the stimulation to the needs of a particular patient.

As shown in FIG. 6, the lead configuration may include two leads (e.g., 121-1 and 121-2, collectively referred to herein as 121). In this example, a distal portion 163-1 of the first lead 121-1 is positioned over the greater occipital nerve 101-1 on the right side of the patient and a distal portion 163-2 of the second lead 121-2 is placed over the greater occipital nerve 101-2 on the left side of the patient. The distal portions 163 of the leads 121 shown in FIG. 6 and in the other examples described herein are straight for illustrative purposes only. It will be recognized that the distal portions 163 may alternatively be curved, helical, paddle-shaped, or of any other shape as may serve a particular application.

The distal portions 163 of each of the leads 121 shown in FIG. 6 cover the greater occipital nerves 101 for illustrative purposes only. It will be recognized that the leads 121 may be located at any other stimulation site (e.g., the lesser occipital nerve 102) as may serve a particular application. In some examples, the distal tip of each of the leads 121 is placed four to five centimeters from the midline (i.e., the medial line or plane of the body) to minimize the need to advance the leads 121 following insertion. However, it will be recognized that the leads 121 may be placed any distance from the midline.

Configurations having two leads 121, such as that shown in FIG. 6, are advantageous in applications wherein it is desirable to apply stimulation to multiple stimulation sites. For example, the lead configuration of FIG. 6 may be used to simultaneously apply stimulation to locations on both the right and left sides of the patient. However, it will be recognized that a single lead 121 or more than two leads 121 may be used in accordance with the systems and methods described herein.

The leads 121 are shown in FIG. 6 to be implanted over the patient's neck at or near the base of the skull in the C1 region. The leads 121 may additionally or alternatively be implanted over the scalp of the patient or at any other suitable location.

A number of suture sleeves 160 may be used to help minimize or eliminate migration of the leads 121 within the patient. FIG. 7A is a perspective view of an exemplary suture sleeve 160 that may be used in accordance with the systems and methods described herein. FIG. 7B is a top view of the suture sleeve 160 illustrated in FIG. 7A. As shown in FIG. 7A, the suture sleeve 160 includes a main body 170 with a lumen 171 extending therethrough. The lumen 171 is dimensioned so as to allow passage therethrough of one of the leads 121.

As shown in FIGS. 7A-7B, one or more slits 172 may be included along the main body 170 of the suture sleeve 160 through which an adhesive may be inserted into the lumen 171 to secure the lead 121 to the suture sleeve 160. In some examples, the adhesive may initially be in a liquid state and solidify upon being inserted into the lumen 171. In this manner, the adhesive may be configured to minimize the risk of lead slippage or migration. Any suitable surgical adhesive may be used including, but not limited to, cyanoacrylate, Duraseal™, TRUFILL® n-BCA, BioGlue™ Surgical Adhesive, Tisseal, Fibrin, and Med A.

The slit 172 also serves to prevent bunching as a suture is tied around the main body 170 of the suture sleeve 160. The suture that is tied around the main body 170 of the suture sleeve 160 will be described in more detail below.

FIGS. 7A-7B show that the suture sleeve 160 may also include a number of wing members 173 extending away from the main body 170. Each of the wing members 173 includes a hole 174 through which a suture can be sewn to secure the suture sleeve 160 in place, for example, to fascia. The suture sleeve 160 shown in FIGS. 7A-7B includes two wing members 173 for illustrative purposes only. It will be recognized that any number of wing members 173 may be included through which sutures may be sewn to anchor the suture sleeve 160 in place. Additionally or alternatively, the suture sleeve 160 may include one or more anchors, hooks, adhesives, or other securing devices that are configured to secure the suture sleeve 160 in place.

FIGS. 7C-7D show variations of the suture sleeves 160 that may be used in connection with the systems and methods described herein. For example, as shown in FIG. 7C, the suture sleeve 160 may be generally cylindrically shaped and include multiple slits 172 extending therethrough. Additionally or alternatively, as shown in FIG. 7D, the suture sleeve 160 may include a number of grooves 175 disposed on its main body 170. These grooves 175 may be configured to guide and retain placement of one or more sutures that are used to secure the lead 121 in place. It will be recognized the suture sleeves 160 may include additional or alternative features as may serve a particular application.

Returning to FIG. 6, each lead 121 is secured by one or more suture sleeves 160—e.g., a distal suture sleeve 160-1 and a proximal suture sleeve 160-2. The proximal suture sleeve 160-2 is closer to the stimulator (not shown) than is the distal suture sleeves 160-1. It will be recognized that any number of suture sleeves 160 may be used to secure the leads 121 in place. Moreover, it will be recognized that any other securing device may additionally or alternatively be used to secure the leads 121 in place. Such securing devices may include, but are not limited to, one or more sutures, hooks, adhesives, or anchors.

Each suture sleeve 160 may be sutured into place using one or more sutures 161. In some examples, the sutures are non-absorbable. Exemplary non-absorbable sutures that may be used to suture the suture sleeves 160 into place include, but are not limited to, a braided nylon (e.g., Nurolon), a braided polyester (e.g., Ethibond or Mersiline), Prolene, Surgilene, Tevdek, a polypropylene material, a braided polyester material, and a Teflon coated polyester material.

In some examples, at least two sutures 161 are used to affix a particular suture sleeve 160 to fascia. These sutures 161 may be threaded through the holes 174 that are a part of the wing members 173. At least one additional suture 161 may be cinched around the main body 170 of the suture sleeve 160 to prevent slippage of the lead 121 within the suture sleeve 160. Although three sutures 161 are illustrated as affixing each suture sleeve 160 in FIG. 6, it will be recognized that any number of sutures 161 may be used to affix each suture sleeve 160 as may serve a particular application.

In some examples, each distal suture sleeve 160-1 may be sutured or otherwise fixed to fascia or any other securing site that is located in the same rostro-caudal motion segment as the most proximal electrode 122 on the lead 121 to minimize relative movement between the target stimulation site (e.g., the greater occipital nerve 101) and the distal suture sleeve 160-1. For example, if the most proximate electrode 122 to the distal suture sleeve 160-1 is located in the C2 region, the distal suture sleeve 160-1 is sutured to fascia in the same C2 region. Likewise, if the most proximate electrode 122 to the distal suture sleeve 160-1 is located in the scalp region, the distal suture sleeve 160-1 is sutured to fascia overlying the scalp.

As shown in FIG. 6, the long axis of each distal suture sleeve 160-1 is substantially collinear with the long axis of the electrode region of its corresponding lead 121. Each lead 121 passes through the lumen 171 of its corresponding distal suture sleeve 160-1 and then forms a loop (e.g., 162-1 and 162-2, collectively referred to herein as 162) of at least 360 degrees. To this end, the leads 121 are configured to pass through corresponding proximal sleeves 160-2, which are positioned so as to maintain the shape of the loops 162. The leads 121 may then be routed to the stimulator (not shown). The portion of the leads 121 that makes up each loop 162 may be made out of any flexible material.

The loops 162 are configured to minimize the forces that are exerted on the distal and proximal sutures sleeves 160-1 and 160-2 when the patient moves his or her head. Hence, the loops 162 are also referred to as “force redirection loops” herein. The force redirection loops 162 are also configured to minimize lead migration. Hence, the force redirection loops 162 may be dimensioned and aligned such that there are minimal forces on either the distal or proximal suture sleeve 160-1 or 160-2.

In some examples, each lead 121 crosses the midline prior to forming its corresponding force redirection loop 162. For example, as shown in FIG. 6, the electrode portion of lead 121-1 is located on the right side of the midline. The lead 121-1 crosses the midline prior to forming force redirection loop 162-1. Lead 121-2 also crosses the midline prior to forming force redirection loop 162-2. Hence, the leads 121 cross each other prior to forming force redirection loops 162. Alternatively, as will be described in more detail below, the leads 121 may be positioned such that they form force redirection loops 162 without crossing each other.

As mentioned, each lead 121 passes through a corresponding proximal suture sleeve 160-2 in forming a force redirection loop 162. As shown in FIG. 6, the long axis of each proximal suture sleeve 160-2 may be substantially perpendicular to the midline or spine. This placement minimizes lead migration that may be caused by the flexion or extension of the neck. Such flexion or extension of the neck may cause the proximal suture sleeve 160-2 to bend, however, the risk of the lead 121 slipping within the suture sleeve 160-2 is minimized when the proximal suture sleeve 160-2 is perpendicular to the midline or spine. Alternatively, as will be described in more detail below, the long axis of the proximal suture sleeve 160-2 may be oriented in any non-parallel direction with respect to the midline.

After the leads 121 pass through corresponding proximal suture sleeves 160-2, the leads 121 are routed to a stimulator 120. In some examples, as will be described in more detail below, the leads 121 may form one or more additional loops prior to being coupled to the stimulator 120. It will be recognized that one or more devices, such as the stimulator 120, may be implanted in any suitable location within the body. For example, the stimulator 120 may be implanted above the iliac crest or over the ribcage to minimize the path of the leads 121 and to minimize the need for multiple lead extensions. Other exemplary implant locations may include, but are not limited to, the buttocks, neck, brain, and subcutaneous area on top of the skull, or any other suitable location within the patient.

FIG. 8 illustrates an alternative lead configuration that may be used in connection with the systems and methods described herein. The lead configuration of FIG. 8 is similar to that described in connection with FIG. 6 in that the configuration includes multiple leads 121 and suture sleeves 160 configured to secure the leads 121 in place. The leads 121 may each include one or more electrodes 122 disposed thereon and are implanted such that one or more of the electrodes 122 are in communication with one or more stimulation sites (e.g., the greater occipital nerves 101).

As shown in FIG. 8, each distal suture sleeve 160-1 may be substantially collinear with the long axis of the distal portion 163 of its corresponding lead 121. Each distal suture sleeve 160-1 is sutured or otherwise fixed to fascia or any other securing site that is located, for example, in the same vertebral level as the most proximal electrode 122 on the lead 121 to minimize relative movement between the target stimulation site (e.g., the greater occipital nerve 101) and the distal suture sleeve 160-1. For example, if the most proximate electrode 122 to the distal suture sleeve 160-1 is located in the C2 region, the distal suture sleeve 160-1 is sutured to fascia in the same C2 region. Likewise, if the most proximate electrode 122 to the distal suture sleeve 160-1 is located in the scalp region, the distal suture sleeve 160-1 is sutured to fascia overlying the scalp.

As described previously in connection with the example of FIG. 6, each lead 121 passes through the lumen 171 of its corresponding distal suture sleeve 160-1 and then forms a force redirection loop (e.g., 162-1 and 162-2) of at least 360 degrees before passing through the proximal sleeves 160-2. However, as shown in the example of FIG. 8, each lead 121 forms the force redirection loop 162 without crossing the other lead 121. For example, lead 121-1 forms force redirection loop 162-1 without crossing lead 121-2. In some examples, each lead 121 forms a force redirection loop 162 without crossing the midline.

As shown in FIG. 8, proximal suture sleeves 160-2 may be provided through which the leads 121 pass. In some examples, each proximal suture sleeve 160-2 may be located at a securing site having a position that is greater than or equal to substantially 180 degrees but less than or equal to substantially 315 degrees along its corresponding force redirection loop 162 as measured from the securing site of its distal suture sleeve 160-1.

To illustrate, a point along the force redirection loop 162-2 corresponding to approximately 180 degrees from the loop's corresponding distal suture sleeve 160-1 is labeled “A”. Likewise, a point along the force redirection loop 162-2 corresponding to approximately 315 degrees from the loop's corresponding distal suture sleeve 160-1 is labeled “B”. Hence, the proximal suture sleeve 160-2 corresponding to the force redirection loop 162-2 shown in FIG. 8 is located in between points A and B.

In some examples, the long axis of each proximal suture sleeve 160-2 is aligned so as to maintain a curve in its corresponding lead 121 of at least 45 degrees between the proximal suture sleeve 160-2 and the stimulator 120. As used herein, the term “maintain a curve” and variations thereof mean ensuring that a curve of at least 45 degrees persists even if the lead 121 is pulled taut between the proximal suture sleeve 160-2 and the stimulator 120. In this manner, the risk of the lead 121 slipping within the suture sleeves 160 is minimized. In some particular examples, the long axis of each proximal suture sleeve 160-2 is aligned so as to maintain a curve in its corresponding lead 121 of at least 90 degrees between the proximal suture sleeve 160-2 and the stimulator 120.

To illustrate an example of this, FIG. 8 shows a configuration wherein each proximal suture sleeve 160-2 is located at a point along its corresponding force redirection loop 162 such that the lumen of each proximal suture sleeve 160-2 is substantially perpendicular to the distal portion 163 of its corresponding lead 121, and thus is also substantially perpendicular to the lumen of its corresponding distal suture sleeve 160-1. Such a configuration may be used to maintain a curve in the leads 121 of at least 45 degrees between the proximal suture sleeves 160-2 and the stimulator 120.

In some examples, the proximal suture sleeves 160-2 are placed caudal to C1 to avoid undesirable suturing over the stimulation site (e.g., the greater occipital nerve 101).

After passing through the proximal suture sleeves 160-2, the leads 121 may each be formed into one or more additional loops (e.g., 180-1 and 180-2, collectively referred to herein as 180) prior to being routed to the stimulator 120. These additional loops 180 may relieve strain that may be placed on the leads 121 by changing size as the patient moves. Hence, these additional loops 180 are referred to herein as “strain relief loops” for illustrative purposes.

FIG. 8 shows that the strain relief loops 180 may be formed at the base of the neck. Additionally or alternatively, the strain relief loops 180 may be formed at any other suitable location as may serve a particular application.

In some examples, the strain relief loops 180 are located within a pocket made by a surgeon in the subcutaneous fat and are not sutured or otherwise affixed to tissue. In this manner, the fat retains the general shape of the strain relief loops 180 while allowing the loops 180 to vary in size as the patient moves.

Additionally or alternatively, the leads 121 may each form a strain relief loop at or near the location of the stimulator 120. For example, if the stimulator 120 is implanted over the ribcage, lead(s) 121 may form one or more strain relief loops at or near the rib cage just prior to being coupled to the stimulator 120.

As mentioned, each suture sleeve 160 described herein may be affixed to fascia. FIG. 9 is a cross-sectional view of an exemplary implanted suture sleeve 160. As shown in FIG. 9, the suture sleeve 160 with a lead 121 disposed therethrough may be located within subcutaneous fat 190 located directly beneath the skin 191. The bottom surface of the suture sleeve 160 is coupled to the fascia 192, which is a thin layer of fibrous tissue that separates the subcutaneous fat 190 from muscle 193.

A number of methods may be used to locate the optimal implantation site for the leads 121. For example, an insulated regional nerve block needle or other probe may be used to identify the location of a desired nerve (e.g., the greater occipital nerve 101) prior to or during the implant procedure. The leads 121 may then be implanted such that the electrodes 122 disposed thereon are in communication with the desired nerve.

Additionally, the patient is often awake and under a local anesthesia for the implantation procedure. Consequently, obtaining verbal feedback from the patient as to the effect of a trial stimulation or various stimulation parameters may be useful in obtaining the most beneficial lead placement and stimulation current parameters. However, it is often difficult to hear the patient due to the orientation of the patient and the dressings used around the implantation procedure. Consequently, a microphone may be placed at or near the patient's mouth. The sound transduced by the microphone may be amplified and/or output through a speaker where it is clearly audible to the personnel performing the testing or implantation of the leads 121. Other patient feedback systems and methods may be used including, but not limited to, keypads, remote controls and other communication devices.

Once the leads 121 are implanted, current steering (also referred to as neuronavigation or e-trolling) may be used to tailor the stimulation to the needs of a particular patient. U.S. Pat. No. 6,393,325, which is incorporated herein by reference in its entirety, discloses an exemplary method of current steering that may be used in connection with the present methods and systems.

By way of example, another exemplary method of using current steering to optimize the stimulation parameters for a particular patient may be carried out according to the following sequence of procedures. For illustrative purposes only, it will be assumed in the example given below that it is desired to apply stimulation to one or more of the occipital nerves 130. The steps listed below may be modified, reordered, and/or added to as best serves a particular application.

1. Beginning with the most distal electrode 122 disposed on the left lead 121-2, steer down until the patient begins reporting paresthesias. Continue steering down one electrode at a time and identify where along the lead 121-2 the paresthesia is the highest and the most intense. Patient feedback and/or some other monitoring device may be used to signal where the paresthesia is the highest and most intense. Mark this location as the optimal stimulation location along this lead 121-2.

2. Repeat step 1 above for the right lead 121-1.

3. For each lead 121, evaluate the distance of the optimal electrode from the midline. If the distance is greater than 30 mm in the neck region, the optimal stimulation site is most likely the lesser occipital nerve 102.

4. If the optimal stimulation site found in step 3 is the lesser occipital nerve 102, repeat steps 1-3 to add a second stimulation site for both leads 121 which is less than 30 mm from the midline. This stimulation site covers the greater occipital nerve 101.

In some instances, it may be desirable to measure the amount of lead migration that occurs over a specific amount of time. For this purpose, a radioopaque bead may be implanted within the patient over the center of the occipital protuberance to provide a landmark in the radiographic plane of the leads. After the lead implant procedure is complete, a true AP fluoroscopic image of the leads 121 and the bead may be printed. Should lead migration be suspected in the future, a second x-ray may be taken with a bead over the occipital protuberance to allow quantitative assessment of lead migration.

An exemplary method of facilitating stimulation of one or more stimulation sites within a patient will now be given in connection with the flow chart of FIG. 10. The steps illustrated in FIG. 10 may be modified, reordered, and/or added to as may serve a particular application. For instance, steps 204 and 205 shown in FIG. 10 may be reversed.

In step 200, a distal portion 163 of a lead 121 is implanted such that the distal portion 163 is in communication with a stimulation site located within a patient. The stimulation site may be located within the head, neck, spinal cord, or at any other location within the patient as may serve a particular application.

The distal portion 163 of the lead 121 is secured at a first securing site with a first securing device (e.g., a suture sleeve or simply a suture) positioned proximal to the stimulation site, as shown in step 201.

A force redirection loop of at least 360 degrees is formed with a portion of the lead 121 that is proximal to the first securing device, as shown in step 202. In step 203, the force redirection loop is secured with a second securing device (e.g., a suture sleeve or simply a suture) at a second securing site. The second securing site may be located at a position that is greater than or equal to substantially 180 degrees but less than or equal to substantially 315 degrees along the force redirection loop 162 as measured from the first securing site.

In step 204, a proximal end of the lead 121 is secured to a stimulator 120. In some examples, the stimulator may be at least partially implanted within the patient.

In step 205, the stimulator and second securing device are positioned to maintain a curve in the lead 121 ofat least 45 degrees between the second securing device and the stimulator 120. In this manner, slippage of the lead 121 within the securing devices may be minimized.

The examples given herein describe various systems and methods for implanting stimulating leads 121. However, it will be recognized that the systems and methods described herein may additionally or alternatively be used in connection with the implantation of catheters.

The preceding description has been presented only to illustrate and describe embodiments of the invention. It is not intended to be exhaustive or to limit the invention to any precise form disclosed. Many modifications and variations are possible in light of the above teaching. 

1. A method comprising: implanting a distal portion of a first stimulating member at a site located to the right of a midline of a patient such that said distal portion of said first stimulating member is in communication with a first stimulation site located within the head or neck of said patient; implanting a distal portion of a second stimulating member at a site located to the left of said midline such that said distal portion of said second stimulating member is in communication with a second stimulation site located within the head or neck of said patient; forming a first loop of at least 360 degrees with a proximal portion of said first stimulating member at a site located to the right of said midline; forming a second loop of at least 360 degrees with a proximal portion of said second stimulating member at a site located to the left of said midline; securing each of said loops to tissue with at least one securing device; and coupling proximal ends of said first and second stimulating members to at least one stimulator.
 2. The method of claim 1, wherein said sites of said first and second loops are located within an upper portion of said neck, and wherein said method further comprises: forming a third loop of at least 360 degrees with said proximal portion of said first stimulating member at a site located within a lower portion of said neck and to the right of said midline; and forming a fourth loop of at least 360 degrees with said proximal portion of said second stimulating member at a site located within a lower portion of said neck and to the left of said midline.
 3. The method of claim 1, wherein said first and second stimulating members each comprise a lead with one or more electrodes disposed thereon, and wherein said method further comprises applying a stimulus generated by said at least one stimulator to at least one of said stimulation sites via at least one of said electrodes.
 4. The method of claim 1, wherein securing each of said loops to tissue with said at least one securing device comprises: securing said first loop with a first securing device to maintain a curve in said first stimulating member of at least 45 degrees between said first securing device and said at least one stimulator; and securing said second loop with a second securing device to maintain a curve in said second stimulating member of at least 45 degrees between said second securing device and said at least one stimulator.
 5. The method of claim 1, wherein the at least one securing device comprises a first securing device and wherein securing each of said loops to tissue with at least one securing device comprises securing said distal portion of said first stimulating member at a first securing site using the first securing device.
 6. The method of claim 5, wherein the at least one securing device further comprises a second securing device and wherein securing each of said loops to tissue with at least one securing device further comprises securing said first loop using the second securing device at a second securing site having a position that is greater than or equal to substantially 180 degrees but less than or equal to substantially 315 degrees along said first loop from said first securing site.
 7. The method of claim 6, wherein said first and second securing devices each comprise a suture sleeve having a lumen configured to facilitate passage therethrough of said first stimulating member.
 8. The method of claim 7, wherein: said lumen of said first securing device is configured to be substantially collinear with said distal portion of said first stimulating member; and said lumen of said second securing device is configured to be substantially perpendicular to said distal portion of said first stimulating member.
 9. The method of claim 6, wherein the at least one securing device further comprises a third securing device and wherein securing each of said loops to tissue with at least one securing device further comprises securing said distal portion of said second stimulating member at a third securing site using the third securing device.
 10. The method of claim 9, wherein the at least one securing device further comprises a fourth securing device and wherein securing each of said loops to tissue with at least one securing device further comprises securing said second loop using the fourth securing device at a fourth securing site having a position that is greater than or equal to substantially 180 degrees but less than or equal to substantially 315 degrees along said second loop from said third securing site.
 11. The method of claim 10, wherein said first, second, third, and fourth securing devices each comprise a suture sleeve having a lumen configured to facilitate passage therethrough of said first or second stimulating member.
 12. The method of claim 11, wherein: said lumen of said third securing device is configured to be substantially collinear with said distal portion of said second stimulating member; and said lumen of said fourth securing device is configured to be substantially perpendicular to said distal portion of said second stimulating member.
 13. The method of claim 10, wherein said fourth securing device is further configured to maintain a curve in said second stimulating member of at least 90 degrees between said fourth securing device and said at least one stimulator.
 14. The method of claim 1, wherein said first stimulating member comprises at least one of a lead having at least one electrode disposed thereon or a catheter.
 15. The method of claim 1, wherein said first stimulation site is a greater occipital nerve, a lesser occipital nerve, or a greater auricular nerve.
 16. The method of claim 15, wherein said second stimulation site is a greater occipital nerve, a lesser occipital nerve, or a greater auricular nerve.
 17. The method of claim 1, further comprising applying a stimulus to at least one of said first stimulation site or second stimulation site using said at least one stimulator.
 18. The method of claim 17, wherein said stimulus is configured to treat a headache.
 19. The method of claim 17, wherein said stimulus is an electrical stimulus.
 20. The method of claim 17, wherein said stimulus comprises an electrical stimulus. 